.\"	$OpenBSD: touch.1,v 1.35 2015/09/25 17:02:57 schwarze Exp $
.\"	$NetBSD: touch.1,v 1.8 1995/08/31 22:10:05 jtc Exp $
.\"
.\" Copyright (c) 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the Institute of Electrical and Electronics Engineers, Inc.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)touch.1	8.3 (Berkeley) 4/28/95
.\"
.Dd $Mdocdate: September 25 2015 $
.Dt TOUCH 1
.Os
.Sh NAME
.Nm touch
.Nd change file access and modification times
.Sh SYNOPSIS
.Nm touch
.Op Fl acm
.Oo Fl d
.Sm off
.Ar ccyy No - Ar mm No - Ar dd Cm T Ar HH : MM : SS Oo \&. Ar frac Oc Op Cm Z
.Sm on
.Oc
.Op Fl r Ar file
.Op Fl t Oo Oo Ar cc Oc Ns Ar yy Oc Ns Ar mmddHHMM Ns Op Pf . Ar SS
.Ar
.Sh DESCRIPTION
The
.Nm
utility sets the modification and access times of files to the
current time of day.
If the file doesn't exist, it is created with default permissions.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl a
Change the access time of the file.
The modification time of the file is not changed unless the
.Fl m
flag is also specified.
.It Fl c
Do not create the file if it does not exist.
The
.Nm
utility does not treat this as an error.
No error messages are displayed and the exit value is not affected.
.It Xo Fl d
.Sm off
.Ar ccyy No - Ar mm No - Ar dd Cm T Ar HH : MM : SS Oo \&. Ar frac Oc Op Cm Z
.Sm on
.Xc
Change the access and modification times to the specified time,
in a format compliant with the
.St -iso8601
standard.
The parts of the argument represent the following:
.Pp
.Bl -tag -width .frac -compact -offset indent
.It Ar ccyy
Year.
.It Ar mm
Month:
a number from 1 to 12.
.It Ar dd
Day:
a number from 1 to 31.
.It Cm T
Either the capital letter
.Sq T
or a single space.
If a space is used, the argument should be quoted to
prevent the shell from splitting it into multiple words.
.It Ar HH
Hour:
a number from 0 to 23.
.It Ar MM
Minute:
a number from 0 to 59.
.It Ar SS
Second:
a number from 0 to 60
(permitting a leap second).
.It Ar frac
The decimal fraction of the second,
either a period or comma,
followed by one or more decimal digits.
.It Cm Z
The timezone specifier: a capital letter
.Sq Z
indicating that the time is in UTC.
If not specified, the time is in the local timezone.
.El
.It Fl m
Change the modification time of the file.
The access time of the file is not changed unless the
.Fl a
flag is also specified.
.It Fl r Ar file
Use the access and modification times from the specified file
instead of the current time of day.
.It Fl t Oo Oo Ar cc Oc Ns Ar yy Oc Ns Ar mmddHHMM Ns Op Pf . Ar SS
Change the access and modification times to the specified time,
where the parts of the argument represent the following:
.Pp
.Bl -tag -width Ds -compact -offset indent
.It Ar ccyy
Year.
If yy is specified, but cc is not,
a value for yy between 69 and 99 results in a cc value of 19.
Otherwise, a cc value of 20 is used.
.It Ar mm
Month:
a number from 1 to 12.
.It Ar dd
Day:
a number from 1 to 31.
.It Ar HH
Hour:
a number from 0 to 23.
.It Ar MM
Minute:
a number from 0 to 59.
.It Ar SS
Second:
a number from 0 to 60
(permitting a leap second),
preceded by a period.
The default is 0.
.El
.El
.Sh EXIT STATUS
.Ex -std touch
.Sh SEE ALSO
.Xr date 1
.Sh STANDARDS
The
.Nm
utility is compliant with the
.St -p1003.1-2008
specification.
.Pp
The obsolescent form of
.Nm touch ,
where a time format is specified as the first argument, is supported.
When no
.Fl d , r ,
or
.Fl t
option is specified, there are at least two arguments, and the first
argument is a string of digits either eight or ten characters in length,
the first argument is interpreted as a time specification of the form
.Dq mmddHHMM[yy] .
.Sh HISTORY
A
.Nm
utility appeared in
.At v7 .
